Three Sligo Institute of Technology students have been hospitalised with meningitis symptoms in recent days.
Two of them are now in a stable condition and one has been discharged, the North Western Health Board said yesterday.
It said close family and friends of the students had been offered antibiotic treatment.
It has also been decided to offer antibiotics to all students and staff in the college today in an attempt to prevent further outbreaks.
Dr Ann Shannon, a specialist in public health medicine with the health board, warned parents and young people to be alert to the disease's symptoms.
These include a high temperature, vomiting, severe headache, joint or muscle pain and cold hands and feet. Other symptoms may include neck stiffness, dislike of bright lights, drowsiness, confusion or the development of a rash.
"Symptoms can be difficult to distinguish from other flu like illnesses. Friends should watch out for one another when ill. A person may be sicker than usual or a rapid change in what appears to be a minor illness should alert. If in doubt seek medical advice," she said.